1. Field of the Invention
The system of the present invention relates to high torque and high capacity rotatable center core and floatable seal body assemblies with universal ram applications and the method of undertaking same. More particularly, the present invention relates to an apparatus that would allow one to pick up the entire weight of the drill string tubing or pipe which would allow one to rotate from the top and have the torque completely through it while rotating.
2. General Background of the Invention
In undertaking wireline work utilizing a side entry device in the present state of the art, the device includes a packoff assembly or grease seal assembly at the entry to the side entry port or top entry port which provides for protection against blowouts while the device is in use. However, while wireline is being lowered through the device, there must be an additional method to seal off the passageway while the wireline is in place. Therefore, there are provided blowout preventors positioned below the wireline packoff on the side entry device which may be manually or hydraulically closed to seal oft the wireline in case of a blowout. Such blowout preventors are manufactured by, for example, Bowen Inc. under the name.
However, it would be beneficial to have such a blowout preventor located in the drill string itself, above the rig floor, which would allow the wireline to be sealed off below the swivel. In that manner, when the drill string below the swivel needs to be rotated to provide torque, the blowout preventors would simply rotate with the drill string. However, in the case of a blowout, or in the event work needed to be done above the swivel above this side entry device, while the well is under pressure, the blowout preventors could be closed off. The type of blowout preventors currently used, as discussed above, manufactured by Bowen Inc., would not have the capability of being placed within the drill string, since the device could not withstand the enormous weight of the drill string below the preventors. So, there is a need for a type of blowout preventors that can be positioned below the swivel, within the drill string, that can be maintained open, and allow to rotate freely with the string, but in the event work needed to be done above the device, the blowout preventors would be closed, and the well, although under pressure would not be capable of blowing out during the curative work. The system of the present invention solves many problems in the art.
An apparatus for use in a drill string is disclosed. The apparatus comprises an inner core assembly having a first and second transverse bore, and has a shoulder formed thereon. A first outer core assembly is slidably disposed about the inner core assembly and rests on the shoulder. The outer core assembly has a first and second transverse bore that is aligned with the first and second transverse bore of said inner core assembly.
The apparatus further comprises a first piston means, disposed within the first and second transverse bore of the outer core assembly, for closing an internal longitudinal bore of the inner core assembly. The apparatus further comprises a ring inserted into an indentation on the inner core assembly, with the ring abutting a top surface of the outer core assembly. A pin means for maintaining the inner core assembly in line with the first outer core assembly may also be included. In one of the preferred embodiments, the inner core assembly is connected at one end to a drill string and at the other end to a swivel.
In one embodiment, the first piston means comprises a first piston member disposed within the first transverse bore of the outer core assembly, a second piston member disposed within the second transverse bore of the outer core assembly, and means for moving the first and second piston member into the internal longitudinal bore of the inner core assembly in order to close seal the internal bore. The first piston member may include a first sleeve disposed within the first transverse bore of the outer core assembly; and the second piston member may include a second sleeve disposed within the second transverse bore of the outer core assembly.
In one of the embodiments, the apparatus further comprises a third and fourth transverse bore positioned within the inner core assembly and a third and fourth transverse bore positioned within the first outer core assembly that is aligned with the third and fourth transverse bore of the inner core assembly. A second piston means, disposed within the third and fourth transverse bore of the outer core assembly, is included for closing the internal longitudinal bore of the inner core assembly.
In another embodiment, a second outer core assembly is slidably disposed about the inner core assembly and rests on a first outer surface of the first outer core assembly, and wherein the second outer core assembly has a third and fourth transverse bore that is aligned with a third and fourth transverse bore located within the inner core assembly. With this embodiment, a second piston means, disposed within the third and fourth transverse bore of the second outer core assembly, is included for closing the internal longitudinal bore of the inner core assembly. In this embodiment, the first and second piston means comprises: a first piston member disposed within the first transverse bore of the first outer core assembly; a second piston member disposed within the second transverse bore of the first outer core assembly; a third piston member disposed within the third transverse bore of the second outer core assembly; a fourth piston member disposed within the fourth transverse bore of the second outer core assembly; and, means for moving the first, second, third, and fourth piston members into the internal longitudinal bore in order to close the internal longitudinal bore.
A method of sealing off flow in a work string is also disclosed. The method comprises providing an apparatus containing an inner core assembly having a first and second transverse bore, and a shoulder formed thereon; a first outer core assembly slidably disposed about the inner core assembly and resting on the shoulder, the outer core assembly having a first and second transverse bore that is aligned with the first and second transverse bore of the inner core assembly; first piston means, disposed within the first and second transverse bore of the outer core assembly, for closing an internal longitudinal bore disposed through the inner core assembly.
The method further comprises connecting the work string to the inner core assembly and transmitting the weight of the drill string to the inner core assembly. Next, the work string is rotated so that a torque is created, and the torque is transmitted through the inner core assembly. The rotation of the work string is terminated. The first piston means is closed in order to close off the internal longitudinal bore of the inner core assembly. Next, the first piston means is opened thereby opening the internal longitudinal bore.
A concentric work string, such as wireline, is provided within the internal longitudinal bore. The concentric work string may have attached thereto a down hole assembly. The concentric work string is run down the work string with the down hole assembly. Next, the first piston means is closed about the wireline within the internal longitudinal bore. Curative work may be performed on the wireline above the first piston means. Next, the first piston means is opened so that the internal longitudinal bore is unsealed. The concentric work string can then be pulled from the work string.
In another embodiment, at least one blowout preventor is positioned within the drill string, above the rig floor, between a swivel and a length of drill pipe below. The apparatus includes an outer core assembly (sometimes referred to as a principal body portion) having a central bore for accommodating an inner core assembly (sometimes referred to as a central assembly), having a first end attached to the lower end of the swivel, and a lower end attached to the drill pipe below. The inner core assembly would include a central bore for accommodating the passage of fluid, tubulars and/or wireline therethrough; there is further provided a pair of transverse bores which would be aligned with the pair of traverse bores in the outer core assembly so as to provide a piston within the bores, capable of moving into the central bore of the inner core assembly to seal the cental bore from flow therethrough; there is further provided a sleeve slidably engaged within the transverse bores for aligning the bores of the body and the inner core assembly; the inner core assembly would provide an annular shoulder around its lower portion so that the outer core assembly would rest upon when the transverse bores are aligned; there would be provided an upper ring in the wall of the inner core assembly to maintain the outer core assembly in place between the shoulder and the upper ring; further, there are provided sealing rings to prevent fluid in the pistons of the apparatus from seeping into other parts of the assembly. There may be provided a plurality of the blowout preventors stacked one upon the other, which would allow multiple sealing off of the wireline, or other small pipe as wash pipe or coiled tubing, but would not be interconnected so as to avoid potential stretching when the inner core assembly must take the weight of the drill string down hole.
The apparatus and method involved would allow one to pull on a center core and have the block with the rams without exerting any pull on the outside body of the block, which would allow one to rotate the drill string without having the torque on the outer core assembly exerted. By using a separate outer core assembly in the system, if the inner core assembly would have stretch and torque, the outer core assembly would be spared from the same stretch and/or torque.
This system could be used when the wire of a wireline unit balls up under the pack off or grease head flow tubes. The operator could close off the apparatus and perform the curative work desired above the apparatus. If an unexpected pressure is exerted on the well, in order to correct the problem, one will close the rams in order to seal off the pressure; then the operators would bleed off above the rams. If one has a pump down tool below the rams, this would allow one to pump fluids downhole if one would need to kill the well.
A method of sealing off flow in a tubular string while using a concentric work string is also disclosed. The concentric work string can be a coiled tubing string. The method comprises providing a sealing apparatus having an inner core assembly and an outer core assembly. The method includes connecting the tubular string to a first end of the inner core assembly and connecting a swivel to a second end of said inner core assembly. Next, the weight of the tubular string is transmitted to the inner core assembly, and the coiled tubing is lowered into the tubular string and through the internal bore of the inner core assembly, and wherein the coiled tubing disposed within the tubular string creates an annular space.
The method further includes rotating the tubular string so that a torque is created, and transmitting the torque through the inner core assembly. Rotation of the tubular string is terminated and the piston means is closed about the coiled tubing in order to seal off the annular space. Next, a fluid is pumped through a side entry sub located below the apparatus, the fluid being pumped into the annular space.
The method further comprises opening the piston means so that the annular space is unsealed and running into the well bore with the coiled tubing to a desired depth. Next, the piston means is closed about the coiled tubing thereby closing the annular space. The method may further comprise opening the piston means so that the annular space is opened and pulling force may be exerted on the tubular string. The weight of the tubular string is transmitted through the outer core assembly. Rotation of the tubular string creates torque which is transmitted to the outer core assembly. Rotation may be stopped and the coiled tubing is pulled out of the tubular string.
It is a principal object of the present invention to provide a blowout preventor system above the rig floor within the drill string to allow sealing off of downhole pressure in order to do work on a side entry or top entry device above the swivel.
It is a further object of the present invention to provide a blowout preventor system in the drill string above the rig floor which can withstand the weight of the drill string without damage to the blowout preventors.
It is a further object of the present invention to provide a blowout preventor system in the drill string above the rig floor which would allow for a plurality of separate outer core assemblies aligned in sequence. This embodiment allows the apparatus to withstand the weight of the drill string but avoid the outer core assembly from being damaged.
It is a further object of the present invention to include a method and apparatus, which would provide a blowout preventor type of seal assembly in the drill string that would allow one to pick up the entire weight of the drill string tubing or pipe and still be able to rotate from the top and have the torque completely go through the apparatus in order to rotate the pipe below it.
It is a further object of the present invention to provide a system which would allow tools or pipe to enter down the center bore of the apparatus, and would allow the apparatus to be closed to control downhole well pressure in the event any tools or pipe above it would need to be worked or changed. Thus, curative work could be performed while controlling well pressure below the apparatus.
It is a further object of the present invention to provide a system for use on chemical cutting or regular logging applications where you can use with high pressure tubing connections or high pressure connections that includes a grease head on top to control well pressure. This would allow one to eliminate the Bowen quick connections which are normally used without elevators and would not have pulled on the tubing below.
It is a further object of the present invention to provide a system which is applicable when doing many types of applications, for instance, the operator is able to pull while chemical cutting the pipe below with heavy loads and still have the availability to rotate the pipe. Prior art blow out preventors cannot rotate or withstand heavy loads. The present invention solves these problem.
An advantage of the High Torque and High Capacity Rotatable Center Core and Floatable Sealed Body Assemblies with Universal Ram Applications and Method is that in the present state of the art, there are no drill pipe blow out preventors (BOP) with seal assemblies that would allow one to pick up the entire weight of the drill string, tubing or pipe without damaging the apparatus. Furthermore, there are no current BOP assemblies which would enable one to rotate from the top and have the torque completely go through the BOP assembly to rotate the pipe below the assembly. The apparatus of the present invention will rotate with the pipe. It could be used when the wireline strands in the grease head and on the pack off assembly have a leak or any of the connections above the assembly within the lubricator are leaking. With the use of the apparatus of the present invention, one would be able to hold the load of the drill string and seal off on any items such as wireline that the seals are installed to fit, and in turn, the operator could correct the problems above the apparatus.